You will notice as you zoom in & out on the screen the dots/dashes remain the same visual size. The same happens on the plot, dots & dashes are the same length on paper for full sheet and plotted zoomed-in area. I think this is a function of the graphics toolkit (QT-4(?)). Somewhere there is/was? a control for the relative lengths of line and space in Medusa at the project level, but I suspect it's been superseded, and in any case Medusa Personal doesn't allow us to change that sort of thing.